Theory-Guided Construction of the Unsaturated V-N2 Site with Carbon Defects for Highly Selective Electrocatalytic Nitrogen Reduction

Renewable energy-driven, electrocatalytic nitrogen reductionreaction(NRR) is a promising strategy for ammonia synthesis. However, improvingcatalyst activity and selectivity under ambient conditions has longbeen challenging. In this work, we obtained the potential active V-Ncenter through theoretical prediction and successfully constructedthe associated V-N-2/N-3 structure on N-dopedcarbon materials. Surprisingly, such a catalyst exhibits excellentelectrocatalytic NRR performance. The V-N-2 catalystaffords a remarkably high faradaic efficiency of 76.53% and an NH3 yield rate of 31.41 mu g(NH3) h(-1) mgCat. -1 at -0.3 V vs RHE. The structural characterizationand density functional theory (DFT) calculations verified that thehigh performance of the catalyst originates from the tuned d-bandupon coordination with nitrogen, in line with the original designintention as derived theoretically. Indeed, the V-N-2 center with carbon defects enhances dinitrogen adsorption and chargetransfer, thereby lowering the energy barriers to form the *NNH intermediates.Such a strategy as a rational design-controllable synthesis-theoreticalverification may prove effective as well for other chemical processes.

Automated summary

In this work, the potential active V-N center was obtained through theoretical prediction and successfully constructed on N-doped carbon materials. The catalyst exhibited excellent electrocatalytic performance for nitrogen reduction reaction with high faradaic efficiency and NH3 yield rate. Structural characterization and density functional theory calculations confirmed the high performance of the catalyst originated from the tuned d-band upon coordination with nitrogen, in line with the original design intention. Such a rational design-controllable synthesis-theoretical verification strategy may be effective for other chemical processes as well.